1. Field of the Invention
The present invention generally relates to an apparatus and method for inputting characters in a portable terminal, and in particular, to an apparatus and method for inputting characters in a portable terminal using a bar-type touch pad.
2. Description of the Related Art
As portable terminals are becoming smaller, lighter, and thinner, their use has risen sharply, in part, because they are very handy to carry. Accordingly, service providers (terminal manufacturers) have been developing terminals with more convenient functions in order satisfy user demands and to secure as many users as possible.
Among various portable terminal functions, users have been preferring additional functions related to messages, such as short messages, multimedia messages, e-mail, broadcast messages, etc., over calling functions. Thus, as the number of character inputs has increased, various methods of efficiently inputting characters have been introduced accordingly.
For example, the CheonJiIn input mode has been conventionally used, as shown in FIG. 1 (CheonJiIn is a Korean word that means heaven, earth, and human). In the CheonJiIn input mode, vowels are categorized into three elements: heaven (•) 103, earth (—) 105, and human () 101. Then, the heaven (•) 103, the earth (—) 105, and the human () 101 are respectively allocated to three keys, and two consonants are allocated to each of the other keys. According to the CheonJiIn input mode, all the vowels can be expressed using combinations of the keys being respectively allocated the above three elements, i.e., the heaven (•) 103, the earth (—) 105, and the human () 101; and all the consonants can be expressed while changing the number of times that each key being allocated two consonants is input.
However, the CheonJiIn character input mode is disadvantageous in that a user must wait for a certain length of time or input a navigation key or a key allocated to a blank character in order to continuously input characters allocated to the same key. Also, since several characters are allocated to one key, the associated key must be continuously pressed three times in order to input a single character.
In the meantime, as portable terminals are becoming smaller and smaller, various methods of minimizing the size of a keypad that normally occupies a considerable space in a portable terminal have been developed and introduced. For example, a touch screen can be included in a portable terminal in order to perform a character input operation in place of a keypad.
However, since a touch screen employs an input mode similar to a keypad, a character adjacent to a desired character may easily and inadvertently be input instead of the desired character. Also, it is impossible to input characters without viewing a screen. Further, when a touch screen is used for a long time, the liquid crystal in the touch screen may likely become damaged.